Densification mechanism of deep low-permeability sandstone reservoir in deltaic depositional setting and its implications for resource development: A case study of the Paleogene reservoirs in Gaoshangpu area of Nanpu sag, China
A better understanding of reservoir densification mechanisms is very important for petroleum exploration and controlling the reservoir quality distribution in low-permeability reservoirs. Low porosity and low permeability, difficult reconstruction, and economic infeasibility are important factors re...
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Frontiers Media S.A.
2022-09-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.996167/full |
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| author | Shilin Wang Xiran Yang Yuanyuan Lu Peidong Su Dong Liu Lingjian Meng Qi Wang Liang Li Ahmed E. Radwan |
| author_facet | Shilin Wang Xiran Yang Yuanyuan Lu Peidong Su Dong Liu Lingjian Meng Qi Wang Liang Li Ahmed E. Radwan |
| author_sort | Shilin Wang |
| collection | DOAJ |
| description | A better understanding of reservoir densification mechanisms is very important for petroleum exploration and controlling the reservoir quality distribution in low-permeability reservoirs. Low porosity and low permeability, difficult reconstruction, and economic infeasibility are important factors restricting its efficient production. Systematic analysis was performed to study the evolution of different microfacies in the deltaic depositional setting of the Paleogene deep low-permeability Gaoshangpu reservoir, define their genetic mechanisms, delineate the dominant facies belts, and define the favorable diagenetic sequences that are important for exploration of high-quality reservoirs. To understand the tight genesis of the low-permeability reservoirs, we analyzed the sedimentological and diagenetic evolution characteristics of various microfacies (i.e., underwater distributary channel, distributary bay, mouth bar, and front sheet sand) using core data and physical property analysis of the reservoir sand body. The results show the underwater distributary channel and estuary bar sand body with medium-to fine-grained and poor–medium sorting. The diagenesis is dominated by strong compaction, calcareous, argillaceous cementation, and dissolution during stage B in early diagenesis and stage A in middle diagenesis. In the fan delta environment, the weak anti-compaction resistance of low-permeability reservoirs is mainly due to the large content of plastic particles, finer grain size, and medium–poor sorting, with an average porosity reduction rate of 65%. This is a key factor for densification of reservoirs above 3000 m. Comparison among different sandstone microfacies of the deltaic setting shows that the sand body of the underwater distributary channel with low shale content has slightly stronger compaction resistance. The porosity reduction is not obvious at the depth of 3,000–4,000 m, but the loss of permeability at this depth section is significant, and the reservoir improvement from later dissolution is most obvious at this depth section. Calcareous cementation is the cause for densification of some mouth bars in the early stage and of underwater distributary channels in the middle and late stage. Under the influence of strong compaction and calcareous-filling pore throat, the sand body of the mouth bar has been basically densified at 3,000 m, resulting in limited reservoir transformation from later dissolution. The study shows that compaction is the main cause of reservoir densification, argillaceous and calcareous cementation is the secondary cause, and later dissolution is another main cause of reservoir enhancement. The research results can provide a reference and direction for reservoir development and search for the high-quality sweet spot in the deep and low-permeability reservoir. |
| first_indexed | 2024-04-14T07:15:21Z |
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| language | English |
| last_indexed | 2024-04-14T07:15:21Z |
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| spelling | doaj.art-f78c659f44be4b8d85855b330b79dcfe2022-12-22T02:06:19ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-09-011010.3389/feart.2022.996167996167Densification mechanism of deep low-permeability sandstone reservoir in deltaic depositional setting and its implications for resource development: A case study of the Paleogene reservoirs in Gaoshangpu area of Nanpu sag, ChinaShilin Wang0Xiran Yang1Yuanyuan Lu2Peidong Su3Dong Liu4Lingjian Meng5Qi Wang6Liang Li7Ahmed E. Radwan8School of Geoscience and Technology, Southwest Petroleum University, Chengdu, ChinaExploration and Development Research Institute, PetroChina Southwest Oil & Gas Field Company, Chengdu, ChinaCNOOC Research Institute Ltd., Beijing, ChinaSchool of Geoscience and Technology, Southwest Petroleum University, Chengdu, ChinaExploration and Development Research Institute, Jidong Oilfield Company, PetroChina, Tangshan, Hebei, ChinaExploration and Development Research Institute, Jidong Oilfield Company, PetroChina, Tangshan, Hebei, ChinaExploration and Development Research Institute, Jidong Oilfield Company, PetroChina, Tangshan, Hebei, ChinaExploration and Development Research Institute, Jidong Oilfield Company, PetroChina, Tangshan, Hebei, ChinaFaculty of Geography and Geology, Institute of Geological Sciences, Jagiellonian University, Kraków, PolandA better understanding of reservoir densification mechanisms is very important for petroleum exploration and controlling the reservoir quality distribution in low-permeability reservoirs. Low porosity and low permeability, difficult reconstruction, and economic infeasibility are important factors restricting its efficient production. Systematic analysis was performed to study the evolution of different microfacies in the deltaic depositional setting of the Paleogene deep low-permeability Gaoshangpu reservoir, define their genetic mechanisms, delineate the dominant facies belts, and define the favorable diagenetic sequences that are important for exploration of high-quality reservoirs. To understand the tight genesis of the low-permeability reservoirs, we analyzed the sedimentological and diagenetic evolution characteristics of various microfacies (i.e., underwater distributary channel, distributary bay, mouth bar, and front sheet sand) using core data and physical property analysis of the reservoir sand body. The results show the underwater distributary channel and estuary bar sand body with medium-to fine-grained and poor–medium sorting. The diagenesis is dominated by strong compaction, calcareous, argillaceous cementation, and dissolution during stage B in early diagenesis and stage A in middle diagenesis. In the fan delta environment, the weak anti-compaction resistance of low-permeability reservoirs is mainly due to the large content of plastic particles, finer grain size, and medium–poor sorting, with an average porosity reduction rate of 65%. This is a key factor for densification of reservoirs above 3000 m. Comparison among different sandstone microfacies of the deltaic setting shows that the sand body of the underwater distributary channel with low shale content has slightly stronger compaction resistance. The porosity reduction is not obvious at the depth of 3,000–4,000 m, but the loss of permeability at this depth section is significant, and the reservoir improvement from later dissolution is most obvious at this depth section. Calcareous cementation is the cause for densification of some mouth bars in the early stage and of underwater distributary channels in the middle and late stage. Under the influence of strong compaction and calcareous-filling pore throat, the sand body of the mouth bar has been basically densified at 3,000 m, resulting in limited reservoir transformation from later dissolution. The study shows that compaction is the main cause of reservoir densification, argillaceous and calcareous cementation is the secondary cause, and later dissolution is another main cause of reservoir enhancement. The research results can provide a reference and direction for reservoir development and search for the high-quality sweet spot in the deep and low-permeability reservoir.https://www.frontiersin.org/articles/10.3389/feart.2022.996167/fullreservoir characteristicsdeep layerlow permeabilitydensificationGaoshangpu oilfieldNanpu sag |
| spellingShingle | Shilin Wang Xiran Yang Yuanyuan Lu Peidong Su Dong Liu Lingjian Meng Qi Wang Liang Li Ahmed E. Radwan Densification mechanism of deep low-permeability sandstone reservoir in deltaic depositional setting and its implications for resource development: A case study of the Paleogene reservoirs in Gaoshangpu area of Nanpu sag, China Frontiers in Earth Science reservoir characteristics deep layer low permeability densification Gaoshangpu oilfield Nanpu sag |
| title | Densification mechanism of deep low-permeability sandstone reservoir in deltaic depositional setting and its implications for resource development: A case study of the Paleogene reservoirs in Gaoshangpu area of Nanpu sag, China |
| title_full | Densification mechanism of deep low-permeability sandstone reservoir in deltaic depositional setting and its implications for resource development: A case study of the Paleogene reservoirs in Gaoshangpu area of Nanpu sag, China |
| title_fullStr | Densification mechanism of deep low-permeability sandstone reservoir in deltaic depositional setting and its implications for resource development: A case study of the Paleogene reservoirs in Gaoshangpu area of Nanpu sag, China |
| title_full_unstemmed | Densification mechanism of deep low-permeability sandstone reservoir in deltaic depositional setting and its implications for resource development: A case study of the Paleogene reservoirs in Gaoshangpu area of Nanpu sag, China |
| title_short | Densification mechanism of deep low-permeability sandstone reservoir in deltaic depositional setting and its implications for resource development: A case study of the Paleogene reservoirs in Gaoshangpu area of Nanpu sag, China |
| title_sort | densification mechanism of deep low permeability sandstone reservoir in deltaic depositional setting and its implications for resource development a case study of the paleogene reservoirs in gaoshangpu area of nanpu sag china |
| topic | reservoir characteristics deep layer low permeability densification Gaoshangpu oilfield Nanpu sag |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.996167/full |
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